1. Field Of The Invention
This invention relates to a hand-operable dispensing package for a viscous product such as a gel, a cream or a paste such as toothpaste. More particularly, this invention relates to a package of the foregoing character in which there is a mechanical connection between a hand-engageable pumping element at an end of a cylindrical container component of the package, and a piston which is initially positioned near the other end of the container and which is mechanically advanced toward the dispensing end as product is dispensed from the container. A package according to the present invention may be provided with striping characteristics, if desired.
2. Description Of The Prior Art
U.S. Pat. No. 4,413,759 (H. Mettenbrink) discloses a prior art hand-operable dispensing package for a viscous product in which the product is contained within a cylindrical portion of the package and is dispensed through a dispensing opening at one end of the container under the influence of a hand-operable pumping element at the one end, in combination with a unidirectionally movable piston which is initially positioned at the other end and which is mechanically linked to the pumping element so that it advances step by step toward the dispensing end of the container as product is dispensed therefrom. In a dispensing package according to this reference, the pumping element functions like a bellows, which requires that it have sufficient flexibility to be collapsible upon the application of a manual dispensing load thereto. This required flexibility limits the appropriate materials of construction for such pumping element to flexible materials such as ethylenevinlyacetate, and these materials are not well-suited to retain a fresh flavor in a packaged product in contact therewith. This is a particular disadvantage in a container intended for the packaging of a product such as toothpaste.
U.S. Pat. Nos. 4,437,591 (A. von Schukmann) and 4,461,403 (H. Prahs) and West German Offenlegungsschrift DE No. 3104726 A1 disclose other versions of hand-operable viscous product dispensing packages, each of which utilizes a pumping element at one end thereof that is mechanically linked to a unidirectionally movable piston which is initially positioned at the other end and which advances step by step toward the dispensing end. However, only the Prahs patent discloses a dispensing package of this general type which is described as having striping capabilities, and this patent teaches a rather complex, and, hence, expensive, structure for accomplishing such a result.